A test handler is an apparatus for testing semiconductor devices in a certain test environment to inspect the qualities of the semiconductor devices after they are fabricated. Techniques related to the test handler are disclosed in many published documents including Korean Utility Model Publication No. 1998-0062568 (entitled “Tray Catcher Of Handler System For Testing Semiconductor Device”), Korean Utility Model Publication No. 1998-0062567 (entitled “Transfer Device Of A Handler System”), Korean Patent Publication No. 2003-0062702 (entitled “Tray Transfer Of Handler For Testing Semiconductor”), Korean Patent Publication No. 2004-0043925 (entitled “Tray Transferring Apparatus”), Korean Patent Publication No. 2002-0031461 (entitled “Tray Transfer For Handler”) and Korean Patent Publication No. 2003-0029266 (entitled “Test Handler”).
To conduct a test by using the test handler, it is required to transfer semiconductor devices from a customer tray, which is used to accommodate the semiconductor devices after their fabrication, into a test tray, which is used to accommodate the semiconductor devices during the test. After the completion of the test, the semiconductor devices should be transferred back into the customer tray. The present invention pertains to a pick and place apparatus for transferring the semiconductor devices between the customer tray and the test tray. For the purpose, the pick and place apparatus includes a plurality of device holding elements operated to grasp or quit the grasp of the semiconductor devices.
As for the customer tray, since the customer tray is used to load or store the semiconductor devices therein, the customer tray is designed to provide a small interval between the semiconductor devices loaded therein to accommodate as many semiconductor devices as possible on the same area. Meanwhile, since a certain amount of interval needs to be maintained between the semiconductor devices for the test of the semiconductor devices, the test tray is designed to provide a relatively larger interval between the semiconductor devices loaded therein, in comparison with the customer tray.
Accordingly, the pitch between the device holding elements of the pick and place apparatus should be at a minimum level when they pick and grasp the semiconductor devices from the customer tray or quit the grasp of the devices, while the pitch should be at a maximum level when the device holding elements pick and grasp the semiconductor devices from the test tray or quit the grasp of them. For the purpose, the pick and place apparatus needs to have a means for controlling the intervals between the plurality of device holding elements in a preset arrangement. Techniques related thereto are disclosed in, for example, Korean Patent Publication No. 10-1998-033607 (entitled “Pick and Place of Semiconductor Device Test Equipment”) that discloses picker interval control means for controlling intervals between pickers which are equivalent to device holding elements in the present invention. More particularly, the picker interval control means includes a pair of interval control cylinders moving in the lengthwise direction; a fixing bracket for fixing the pair of interval control cylinders to a picker assembler; and a pair of fixing blocks attached to both sides of the pair of interval control cylinders to be installed at picker bases of both end portions. According thereto, lengthwise pitches between eight device holding elements are varied by using the pair of interval control cylinders moving in different directions.
In accordance with the above-mentioned equipment, powers of the pairs of the interval control cylinders are applied to a first device holding element and an eighth device holding element of the device holding element, respectively, and the remaining second to seventh device holding elements are moved pursuant to the movements of the first and the eighth device holding elements. Thus, a minimum pitch is determined by widths of the device holding elements, and a maximum pitch is determined by rings for connecting neighboring device holding element(s). Since the first device holding element moves in a direction opposite to the eighth device holding element, a pair of cylinders are required for supplying powers to the first and the eighth device holding elements.
However, the above-mentioned equipment has drawbacks as following. First, since the interval control cylinders need to be used together with solenoid devices and pneumatic pressure applying devices, the production cost and the weight of the equipment as a whole are increased. Further, since the pitches between the device holding elements are increased or decreased due to the movements of the pair of the interval control cylinders that are configured as separate elements, precise interval controls are required for, e.g., adjusting the movements of the pair of the interval control cylinders to be in concord with each other, but such precise controls are difficult to be implemented.